*
 * @author Kevin Bourrillion
 * @author Jesse Wilson
 * @author Austin Appleby
 */
@GwtCompatible
@ElementTypesAreNonnullByDefault
final class Hashing {
  private Hashing() {}

  /*
   * These should be ints, but we need to use longs to force GWT to do the multiplications with
   * enough precision.
   */
  private static final long C1 = 0xcc9e2d51;

 *
 * @author Kevin Bourrillion
 * @author Jesse Wilson
 * @author Austin Appleby
 */
@GwtCompatible
@ElementTypesAreNonnullByDefault
final class Hashing {
  private Hashing() {}

  /*
   * These should be ints, but we need to use longs to force GWT to do the multiplications with
   * enough precision.
   */
  private static final long C1 = 0xcc9e2d51;

    byte result = 0x01;
    // Trick the JVM to prevent it from using the hash function non-polymorphically
    result ^= Hashing.crc32().hashInt(reps).asBytes()[0];
    result ^= Hashing.adler32().hashInt(reps).asBytes()[0];
    result ^= Hashing.fingerprint2011().hashInt(reps).asBytes()[0];
    for (int i = 0; i < reps; i++) {
      result ^= hashFunction.hashBytes(testBytes).asBytes()[0];
    }
    return result;

    byte result = 0x01;
    // Trick the JVM to prevent it from using the hash function non-polymorphically
    result ^= Hashing.crc32().hashInt(reps).asBytes()[0];
    result ^= Hashing.adler32().hashInt(reps).asBytes()[0];
    result ^= Hashing.fingerprint2011().hashInt(reps).asBytes()[0];
    for (int i = 0; i < reps; i++) {
      result ^= hashFunction.hashBytes(testBytes).asBytes()[0];
    }
    return result;

  }

  public void testHash_hashesCorrectly() throws Exception {
    byte[] buf = new byte[] {'y', 'a', 'm', 's'};
    HashCode expectedHash = Hashing.md5().hashBytes(buf);
    HashingOutputStream out = new HashingOutputStream(Hashing.md5(), buffer);

    out.write(buf);

    assertEquals(expectedHash, out.hash());
  }

  public void testChecksForNull() throws Exception {

# OAuth2 mit Password (und Hashing), Bearer mit JWT-Tokens

Da wir nun über den gesamten Sicherheitsablauf verfügen, machen wir die Anwendung tatsächlich sicher, indem wir <abbr title="JSON Web Tokens">JWT</abbr>-Tokens und sicheres Passwort-Hashing verwenden.

Diesen Code können Sie tatsächlich in Ihrer Anwendung verwenden, die Passwort-Hashes in Ihrer Datenbank speichern, usw.

Wir bauen auf dem vorherigen Kapitel auf.

## Über JWT

///

## Password hashing

"Hashing" means converting some content (a password in this case) into a sequence of bytes (just a string) that looks like gibberish.

Whenever you pass exactly the same content (exactly the same password) you get exactly the same gibberish.

But you cannot convert from the gibberish back to the password.

### Why use password hashing

Let's put that data in the Pydantic `UserInDB` model first.

You should never save plaintext passwords, so, we'll use the (fake) password hashing system.

If the passwords don't match, we return the same error.

#### Password hashing

"Hashing" means: converting some content (a password in this case) into a sequence of bytes (just a string) that looks like gibberish.

Sie sollten niemals Klartext-Passwörter speichern, daher verwenden wir ein (gefaktes) Passwort-Hashing-System.

Wenn die Passwörter nicht übereinstimmen, geben wir denselben Fehler zurück.

#### Passwort-Hashing

„Hashing“ bedeutet: Konvertieren eines Inhalts (in diesem Fall eines Passworts) in eine Folge von Bytes (ein schlichter String), die wie Kauderwelsch aussieht.

      V value = entry.getValue();
      checkEntryNotNull(key, value);
      int keyHash = key.hashCode();
      int valueHash = value.hashCode();
      int keyBucket = Hashing.smear(keyHash) & mask;
      int valueBucket = Hashing.smear(valueHash) & mask;

      ImmutableMapEntry<K, V> nextInKeyBucket = keyTable[keyBucket];
      ImmutableMapEntry<K, V> nextInValueBucket = valueTable[valueBucket];
      try {